1. Field of Invention
This invention relates to fuel filter assemblies. Specifically, this invention relates to a fuel filter having a valve and flag indicator that signals a user when the fuel filter should be replaced.
2. Description of Related Art
Various types of fuel filters are known in the prior art. In the case of internal combustion engines, fuel filters insure that clean, filtered fuel is delivered by a fuel pump from a fuel tank to an engine's carburetor or fuel injectors. A typical fuel filter of the prior art may include a filter element enclosed in a housing having an inlet and outlet. The inlet and outlet allow the filter to be connected to a fuel system of an internal combustion engine. The filter element of a typical fuel filter may consist of a frame or reinforcing member connected to a filter media. The filter media may be constructed of a porous material, such as paper or other synthetic material. The filter media traps particulate matter and impurities, while allowing clean fuel to pass on to the engine's carburetor or fuel injectors.
During use, the filter media may become clogged with impurities. As the filter media becomes clogged, the fuel pump discharge pressure, as measured at the outlet of the pump, will increase and the volume of fuel flow to the engine's carburetor or fuel injectors will decrease. Eventually, if left unchecked, the filter media may become so clogged that the fuel pump will no longer be able to provide enough fuel to the engine for normal operation and the engine may stall or refuse to start. Alternatively, the fuel pump may produce enough discharge pressure to rupture the filter element, allowing contaminants and impurities to flow to the carburetor or fuel injectors.
Various methods have been used to determine when a fuel filter should be replaced. For example, some fuel filters of the prior art have transparent housings that allow the user to visually inspect the filter media. If the filter media appears to be dirty the user may disassemble the filter and replace only the filter element, or the user may simply remove and replace the entire filter. Another method commonly employed is to periodically replace the entire filter assembly as part of a routine maintenance program. Other filter assemblies may be periodically disassembled and cleaned.